Reproduction as a Function of Living Conditions: The Breeding Biology of the Radiated Tortoise (Astrochelys radiata) under Natural and Captive Conditions in Southwest Madagascar

Abstract

Abstract The Radiated Tortoise (Astrochelys radiata) is one of Madagascar's four critically endangered tortoise species that has been heavily impacted by poaching. Despite successful captive breeding programs for this species, within Madagascar and internationally, little information is available detailing their reproductive ecology in the wild. In this study, I compare the characteristics of this species' reproduction and reproductive success in 1) a wild population (WP) within their natural habitat in Tsimanampetsotsa National Park, and 2) a captive population (CP) that is exposed to regional climatic conditions in southwest Madagascar. Breeding activities were seasonal, with egg depositions from February until October and mean (±SD) clutch sizes of 3.4 ± 1.6 eggs (CP) and 2.5 ± 0.5 eggs (WP). I found egg mass to be positively correlated with female body mass, and the CP tortoises were larger than in the WP. Egg masses in the CP (36.6 ± 6.4 g) were higher than in the WP (30.1 ± 4.0 g). Incubation time w...